1. The Field of the Invention
The field of the invention relates to an improvement in cordless telephone sets and more particularly the means by which such a set makes connection with a limited range radio base station which is wired to a conventional telephone station for the purpose of making the set, in effect, a low power radio transmitter/receiver and simultaneously an improved means of selecting different telephone lines. The term "cordless" is used herein to distinguish the field of invention from the more general field of wireless telephony which encompasses the use of powerful radio devices and has considerably different problems not the least of which is transmission and reception over relatively long distances.
2. DESCRIPTION OF PRIOR ART
The background art of the invention reveals remarkable advances in consumer-oriented telephone hand sets which are cord-free. Conventionally, a modification is made at the telephone station during installation by attaching thereto a so-called radio base station which is activated by telephone switching devices to allow duplexing and to enable an individual to receive or to make telephone calls through a cordless hand set by means of radio signals picked up at the hand set or sent therefrom to the base.
The convenience to the user is obvious and the great commercial, popular demand for this kind of product demonstrates the utility of thereof.
Recently, as set forth for example in Popular Science Magazine, August, 1983, p. 23, attempts have been made to convert a hand-held cordless telephone set to one which may be worn by the user as a headset. Some models currently available show portions of the apparatus fitted conventionally to the head by means of an arctuate band-like arrangement of metal or plastic conforming to the contour of the head, upon which arrangement are located an earphone and a microphone containing mouthpiece on an arm generally in a fixed position adjacent to the mouth of the user. A small swivel adjustment is sometimes made available at the base of the mouthpiece arm permitting small relocations thereof relative to the mouth to improve transmission quality and user comfort. The radio unit portion of the set in this mode is worn on the waist, as for example, by means of a belt, and connected to the headset portion by means of wires. The power switch is typically located on the belt-worn portion of the radio unit and is operated manually, typically by means of a push button.
The problems encountered by the configuration so disclosed are relate to convenience and accessability. The power switch may be at times inaccessable to the user by virtue of his position or because it is not locatable without lowering the eyes, thereby diverting the attention visually, and the mouthpiece is continually in front of the face, obstructing it and the lower field of vision when the telephone is not in use. Additionally, rapid, easily accessable means for selecting different telephone lines are not provided.
The present invention obviates the difficulties above-disclosed and provides a simple, inexpensive modification to cordless telephone headsets by providing an uncomplicated, foolproof means of making the telephone set connect with and select telephone lines while simultaneously providing a simple means for relocating the mouthpiece entirely away from the face while automatically disconnecting the radio unit, but leaving the whole apparatus continuously accessable.
By way of example, and not limitation, in addition to the more obvious, ordinary implementations, the inventive improvement herein disclosed has great utility in areas where it is desirable for the user to maintain telephone communication while in a confined space or where his field of vision should not be impaired unnecessarily. Structural construction workers, marine vessel operators, vehicle drivers, warehouse personnel, and even forward observers in military situations will benefit substantially from the convenience and accessability provided by this invention.